This invention relates to an agricultural frame for transporting ground working tools and particularly to a frame for a cultivator of the type including a frame mounted on ground wheels and including a hitch for transporting the frame across the ground, the frame carrying a plurality of cultivator shanks each having a ground cutting tool for providing a cultivation action on the ground.
Cultivator frames of this type generally carry a cutting tool of the type having a front point and two diverging wings extending outwardly and rearwardly to provide a cutting action under a top surface of the ground.
In recent years many such cultivators have been manufactured and arranged for dual purposes that is an initial cultivating action usually in the fall for the purpose of turning the soil to incorporate crop residue and secondly for seeding in the spring. For cultivating the depth of the cutting action is generally deeper but does not need to be so accurately controlled. For seeding, seed tubes are provided on the frame and transport seeds to each of the cultivator shanks so the seeds are discharged underneath the cutting tool to lay the seeds in a row. For this purpose the cutting tool has to be accurately controlled so that the seeds are laid within a predetermined depth band. Excessive variations of the depth will vary the germination characteristics and lead to an uneven crop.
A lot of attention has therefore been applied to the design of the cultivator frame so as to support the shanks and the cutting tools or sweeps at a required height relative to the ground. Further considerations which must be taken into account in the design of the cultivator frame include the necessity for height adjustment to accommodate the different actions and to accommodate different crop varieties. Furthermore recent agricultural practices have significantly increased the amount of crop residue remaining on the ground after the harvesting has been completed. It is necessary therefore in a cultivator design to reduce the possibility of blockages occurring in the operation of the cultivator by collecting the crop residue into a bunch around the cultivator shanks. A yet further requirement in the design of a cultivator frame is that of converting the frame to a transport position.
One example of a conventional cultivator frame arrangement is shown in a brochure by John Deere entitled Seed Bed Tillage Equipment and in particular the 1060 Field Cultivator, This arrangement includes a center section towed by a hitch behind the tractor and two wing sections each extending out to a respective side of the centre section. Each wing section is formed of two separate portions including an inner portion and an outer portion connected at an outer end of the inner portion. Each of these portions includes ground wheels for supporting the portion in movement across the ground. In moving the transport, the outer wing portion folds inwardly on to the top of the inner wing portion following which the inner wing portion is folded upwardly so as to stand upwardly approximately at right angles from the end of the center section. This transport position is generally unsuitable because it mounts a very high load on the center section during the transport movement and since the dimensions of the folded frame are relatively wide and very high so that the frame is difficult to move through restricted areas and particularly under bridges.
A further disadvantage of this type of frame is that it is necessary to individually adjust the height of the frame sections so that a large number of hydraulic cylinders are required to operate this adjustment generally by raising and lowering the wheels.
The cultivator sweeps of course must cooperate to act across the full width of the cultivator frame but it is of course not possible to locate them side by side in a single row in view of spacing problems and also in view of the tendency of such an arrangement to carry the crop residue in the form of a rake. The shanks are therefore mounted on a plurality of parallel bars and generally at least three such bars are used so as to triple the amount of space between each shank on a bar and the next adjacent shank. One further disadvantage of the above type of cultivator frame is that the frame requires wheels located in the area of the cultivator shanks. Thus the wheels are rolling in the soil which has already been worked with the danger that the wheels will pick up moist soil which will eventually interfere with the proper rolling action of the wheel. In addition the location of the wheels within the area of the shanks requires a yet further increase in the spacing between the shank so it is often necessary to increase the number of bars from three up to as many as five. Such a five bar arrangement of course significantly increases the dimensions and weight of the frame and increases the distance between the front shanks and the rear shanks of the array.
Other examples of cultivator frame of the above general type are used by other manufacturers and include the same disadvantages, Some manufacturers have also attempted to increase the ability of the frame to follow the contours of the ground by allowing an increased floating action between one frame section and the next frame section and this arrangement yet further increases the number of wheels necessary for supporting the frame and further increases the size and weight of the frame thus further exacerbating the problems defined above.
It is also known to mount a relatively narrow cultivator frame directly on a three-point hitch of a smaller power tractor. One such example of a frame of this type is shown in a brochure by Morris Industries of Yorkton, Saskatchewan, Canada. This frame includes a three bar support for the shanks and two gauge wheel at sides of the frame which support the frame at a pre-set distance from the ground as the frame is free to float upwards and downwards on the three-point hitch. This arrangement is only suitable for very narrow implements and is therefore not suitable for the high productivity farms of today where up to sixty feet in width is required for a single pass of the cultivator frame.
It is also known to provide another form of agricultural tool bar for pulling ground working elements such as harrows, packers, rakes and the like in which the tool bar is arranged as a single elongate element with a longitudinal axis at right angles to the direction of movement of the tool bar across the ground. The tool bar is split into a center section and two wing sections with the center section mounted on two ground wheels spaced apart along the center section and each wing section includes a ground wheel adjacent an outer end. The inner end of each wing section is attached to a respective outer end of the centre section by a pivot coupling which allows pivotal movement about two mutually perpendicular axes each of which axis is at right angles to the longitudinal axis of the tool bar. This pivot coupling arrangement is arranged so that when the tool bar is rotated through 90.degree., the wing sections can pivot about a vertical axis transverse to the longitudinal axis so that the wing section moves rearwardly to trail from the outer end of the center section.
Examples of arrangements of this type are shown in Canadian Patents 1,267,318 (Just et al assigned to Morris Rod Weeder) and 1,099,566 (Summach et al assigned to Flexi-Coil Ltd.) and in U.S. Pat. Nos. 3,935,696 (Pavel) and 4,418,762 (Page assigned to Western Manufacturing Co.).
Each of these arrangements includes a tool bar in which the center section of the tool bar is mounted on a rear end of the hitch frame behind the ground wheel supporting the hitch frame. The tool bar is then actuated by a hydraulic cylinder so that it rotates about an axis generally slightly offset from the longitudinal axis of the tool bar itself without rotation being affected while the hitch frame and the wheels on the hitch frame remain stationary. Generally the outer wheel at the end of the wing section is arranged with its rotation axis lying on the longitudinal axis of the tool bar. A second wheel is usually provided with its rotation axis at right angles to the longitudinal axis of the tool bar so that when the tool bar rotates the second wheel engages the ground and lifts the first wheel away from the ground. In this way there is no need to adjust the angle of the wheel at the end of the wing section to accommodate the working position and the trailing position. However the above patent to Pavel shows an arrangement in which the wheel at the end of the wing section can be manually rotated about a vertical axis so that the single wheel carries the wing section in both the operating position and the trailing position.
Tool bars of this type are generally used with tools such as harrows, packers and the like which do not require an accurate depth control but instead are generally merely suspended from the tool bar to take up their own height by engagement with the ground surface.
A brochure of Western Manufacturing which shows the machine of the above United States patent also includes an arrangement in which a plurality of S-tine cultivator teeth are mounted on bars parallel to the tool bar and spaced rearwardly from the tool bar on arms extending rigidly from the tool bar in a horizontal direction. Height adjustment is effected by vertical movement of the wheel relative to the bar thus requiring a hydraulic cylinder for each of the wheels. The S-tines are intended to carry simple points rather than a sweep since the S-tine arrangement does not carry the sweep at a constant angle of attack which is required to maintain the sweep at the required depth.